Counteractive effects of norepinephrine and amphetamine on quabain-induced amnesia.

Ouabain, administered 5 min prior to learning induces amnesia for a single-trial passive avoidance task in day-old chickens by inhibiting memory formation during the labile sodium-pump dependent phase. Amphetamine and norepinephrine (NE) successfully counteract ouabain-induced amnesia when administered immediately after learning. The actions of these drugs on ouabain-induced amnesia parallel that of diphenylhydantoin (DPH), and within similar time constraints. It is concluded that amphetamine (through release of NE) and norepinephrine exert their effects through stimulation of Na+/K+ ATP'ase activity. This conclusion is supported by the observation that these drugs do not overcome potassium chloride (KCl) inhibition of memory formation in the short-term phase prior to formation of labile sodium-pump dependent memory, and the fact that the noradrenergic blockers, propranolol and piperoxane do not alter the couteractive influence of DPH on cycloheximide (CXM) inhibition of the protein synthesis dependent long term memory phase which follows the labile phase.